Answer:
The formula for calculating the width of the window is

Step-by-step explanation:
<u><em>The question in English is</em></u>
A rectangular window is l meters wide and h meters high, with a perimeter of 6 meters and an area of 2m². What is the formula for calculating the width of the window?
we know that
The perimeter of the window is equal to

we have

so

simplify
isolate the variable l
----> equation A
The area of the window is equal to

we have

so
----> equation B
substitute equation A in equation B
solve for w

The formula to solve a quadratic equation of the form
is equal to
in this problem we have

so
substitute in the formula
---> formula for calculating the width of the window
Answer:
x=15
Step-by-step explanation:
21:2x=7:10 can be rewritten as 21/2x=7/10
21/2x=7/10, cross multiply
= 14x=210
x=15
Answer:
-x²+9x+4
Step-by-step explanation:
Hope this helps!
First of all, you have to find the area of both triangles:


Or just 16 because there are 2 of the same triangles.
Now you have to find the area of the 3 rectangles.
The two that are in the front are 4*3 (l*h) or 12*2 (because there are 2 congruent rectangles. The area of those rectangles is 24 square mm.
Now you find the area of the back rectangle:
5.7*3 = 17.1
Finally, you add all the found numbers to figure out the surface area.
17.1 + 16 + 24 = 57.1 square millimeters.
Hope this helped,
Loafly